News / Science & Technology

Research Suggests Prehistoric Man First Influenced Climate Change

Early farmers' use of controlled forest burns, like this one in current-day Uganda, could have begun releasing climate changing gases into the atmosphere 8,000 years ago.
Early farmers' use of controlled forest burns, like this one in current-day Uganda, could have begun releasing climate changing gases into the atmosphere 8,000 years ago.

There is new evidence supporting a controversial theory that humans began changing the earth's climate with the development of agriculture some 8,000 years ago.

In an article published in the journal Nature, researchers studying the theory say new data indicate that enormous amounts of earth-warming greenhouse gases released into the atmosphere by early farming activities helped ward off an impending ice age, and fostered the planet’s current relatively warm, stable climate.  

A more commonly accepted theory suggests that man’s first major influence on the earth’s climate began in the 18th century, at the dawn of the industrial age.   

Scientists say the new findings indicate that the earth was spared from another long deep freeze after the last Ice Age ended 11,000 years ago because of an unusual rise in atmospheric carbon dioxide and methane gas levels starting about 3,000 years later.  

The increase coincided with the advent of farming practices - including the clearing and burning of forests, and maintaining large herds of livestock - that released more of those heat-trapping gases into the atmosphere.

Prehistoric climate expert William Ruddiman of the University of Virginia first proposed the theory in 2003. He said the new findings supporting his hypothesis will be published in a series of papers later this year in a special issue of the journal The Holocene.

Critics of the theory say human populations 8,000 years ago were too small to produce enough greenhouse gases to influence global climate change. And they suggest that other causes, including changes in the earth's orbit and a variety of natural events, could explain the unusual rise in greenhouse gases.

Greenhouse gases are man-made and naturally-occurring gases that trap solar heat in the earth’s atmosphere.

Most scientists now believe that modern man’s burning of fossil fuels and the clearing of forests over the past two centuries have intensified the so-called "Greenhouse Effect" and have caused a gradual warming of the earth's climate.

You May Like

Multimedia Social Media Documenting, Not Driving, Hong Kong Protests

Unlike in Arab Spring uprisings, pro-democracy protesters in Hong Kong aren't relying on Twitter and Facebook to organize, but social media still plays a role More

Analysis: Occupy Central Not Exactly Hong Kong’s Tiananmen

VOA's former Hong Kong, Beijing correspondent compares and contrasts 1989 Tiananmen Square protest with what is now happening in Hong Kong More

Bambari Hospital a Lone Place of Help in Violence-Plagued CAR

Only establishment still functioning in CAR's second city is main hospital More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
The Legacy of Jimmy Carter: The Preacher from Plainsi
X
October 01, 2014 10:45 AM
It is common in the United States to see tourists flock to sites associated with America's presidents. Some are privately owned and others are run by the National Park Service or the National Archives -- but most have helped draw business and people into the towns and cities where they are located. As VOA’s Kane Farabaugh reports, there is one particular presidential hometown that is unique in what it has to offer those who make the trip.
Video

Video The Legacy of Jimmy Carter: The Preacher from Plains

It is common in the United States to see tourists flock to sites associated with America's presidents. Some are privately owned and others are run by the National Park Service or the National Archives -- but most have helped draw business and people into the towns and cities where they are located. As VOA’s Kane Farabaugh reports, there is one particular presidential hometown that is unique in what it has to offer those who make the trip.
Video

Video Hong Kong Protests Draw New Supporters on National Holiday

On the 65th anniversary of the founding of Communist China, Hong Kong protesters are hoping to stage the largest pro-democracy demonstration since the 1989 Tiananmen protests. VOA's Brian Padden visited one of the protest sites mid-day, when the atmosphere was calm and where the supporters were enthusiastic about joining what they are calling the umbrella revolution.
Video

Video India's PM Continues First US Visit

India's prime minister is on his first visit to Washington, to strengthen political and economic ties between the world's oldest and the world biggest democracies. He came to the U.S. capital from New York, the first stop on his five-day visit to the country that denied him an entry visa in the past. From Washington, Zlatica Hoke reports Modi seemed most focused on attracting foreign investment and trade to increase job opportunities for his people.
Video

Video Malaysia Struggles to Stop People Joining Jihad

Malaysian authorities say militant groups like the so-called "Islamic State" have used social media to entice at least three dozen Malaysian Muslims to fight in what they call "jihad" in Syria and Iraq. As Mahi Ramkrishnan reports from Kuala Lumpur, counterterrorism police are deeply worried about what could happen when these militants return home.
Video

Video Could US Have Done More to Stop Rise of Islamic State?

President Obama says airstrikes against Islamic State militants in Syria will likely continue for some time because, in his words, "there is a cancer that has grown for too long." So what if President Obama had acted sooner in Syria to arm more-moderate opponents of both the Islamic State and the Syrian government? VOA State Department Correspondent Scott Stearns reports from the United Nations.
Video

Video Treasure Hunters Seek 'Hidden Treasure' in Central Kenya

Could a cave in a small village in central Kenya be the site of buried treasure? A rumor of riches, left behind by colonialists, has some residents dreaming of wealth, while others see it as a dangerous hoax. VOA's Gabe Joselow has the story.
Video

Video Ebola Patients Find No Treatment at Sierra Leone Holding Center

At a holding facility in Makeni, central Sierra Leone, dozens of sick people sit on the floor in an empty university building. They wait in filthy conditions. It's a 16-hour drive by ambulance to Kailahun Ebola treatment center. Adam Bailes was there and reports on what he says are some of the worst situations he has seen since the beginning of this Ebola outbreak. And he says it appears case numbers may already be far worse than authorities acknowledge.
Video

Video Identifying Bodies Found in Texas Border Region

Thousands of immigrants have died after crossing the border from Mexico into remote areas of the southwestern United States in recent years. Local officials in south Texas alone have found hundreds of unidentified bodies and buried them in mass graves in local cemeteries. Now an anthropologist and her students at Baylor University have been exhuming bodies and looking for clues to identify them. VOA’s Greg Flakus has more from Waco, Texas.
Colonel Steve ‘Spiros’ Pisanos left Greece and came to the U.S. to learn to fly. He flew fighters for the Allies in World War II, narrowly escaping death multiple times.Colonel Steve ‘Spiros’ Pisanos left Greece and came to the U.S. to learn to fly. He flew fighters for the Allies in World War II, narrowly escaping death multiple times.

AppleAndroid